Display device

ABSTRACT

According to one embodiment, a display device includes a first substrate including a light-shielding layer and a conductive line having a first side surface and a second side surface on a side opposite to the first side surface, a second substrate opposed to the first substrate, a polymer dispersed liquid crystal layer held between the first substrate and the second substrate, and including a polymer and liquid crystal molecules, and a light-emitting element opposed to an end portion of at least one of the first substrate and the second substrate, wherein the first side surface is closer to the light-emitting element than the second side surface, and the light-shielding layer covers at least the first side surface of the conductive line.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based upon and claims the benefit of priority fromJapanese Patent Application No. 2017-175057, filed Sep. 12, 2017, theentire contents of which are incorporated herein by reference.

FIELD

Embodiments described herein relate generally to a display device.

BACKGROUND

Recently, various types of illumination devices using polymer dispersedliquid crystal (hereinafter called “PDLC”) capable of switching adiffusing state of diffusing incident light and a transmitting state oftransmitting incident light have been proposed.

In contrast, a display device using PDLC has been required to suppressdegradation in display quality.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view showing a configuration example of a displaydevice DSP according to the embodiments.

FIG. 2 is a perspective view showing the display device DSP shown inFIG. 1.

FIG. 3 is a cross-sectional view showing the display device DSP shown inFIG. 1.

FIG. 4 is a cross-sectional view showing a configuration example of thedisplay panel PNL shown in FIG. 3.

FIG. 5 is a cross-sectional view showing First Embodiment.

FIG. 6 is a cross-sectional view showing Second Embodiment.

FIG. 7 is a cross-sectional view showing Third Embodiment.

FIG. 8 is a cross-sectional view showing a first configuration exampleof First Embodiment.

FIG. 9 is a cross-sectional view showing a second configuration exampleof the First Embodiment.

FIG. 10 is a cross-sectional view showing a third configuration exampleof the First Embodiment.

FIG. 11 is a cross-sectional view showing a fourth configuration exampleof Second Embodiment.

FIG. 12 is a cross-sectional view showing a fifth configuration exampleof the Second Embodiment.

FIG. 13 is a cross-sectional view showing a sixth configuration exampleof Third Embodiment.

FIG. 14 is a cross-sectional view showing a seventh configurationexample of a conductive line 11 and a light-shielding layer 16.

FIG. 15 is a cross-sectional view showing an eighth configurationexample of the conductive line 11 and the light-shielding layer 16.

FIG. 16 is a cross-sectional view showing a ninth configuration exampleof the conductive line 11 and the light-shielding layer 16.

FIG. 17 is a cross-sectional view showing Fourth Embodiment.

FIG. 18 is a cross-sectional view showing Fifth Embodiment.

FIG. 19 is a cross-sectional view showing Sixth Embodiment.

FIG. 20 is a cross-sectional view showing a tenth configuration example.

FIG. 21 is a cross-sectional view showing an eleventh configurationexample.

FIG. 22 is a cross-sectional view showing Seventh Embodiment.

FIG. 23 is an illustration schematically showing a liquid crystal layer30 in a transparent state.

FIG. 24 is an illustration schematically showing the liquid crystallayer 30 in a scattering state.

FIG. 25 is a cross-sectional view showing a display panel PNL in a casewhere the liquid crystal layer 30 is in a transparent state.

FIG. 26 is a cross-sectional view showing the display panel PNL in acase where the liquid crystal layer 30 is in a scattering state.

FIG. 27 is a plan view showing a configuration example of a pixel PX.

FIG. 28 is a cross-sectional view seen along line A-B in the pixel PXshown in FIG. 27.

DETAILED DESCRIPTION

In general, according to one embodiment, a display device includes: afirst substrate including a light-shielding layer and a conductive linehaving a first side surface and a second side surface on a side oppositeto the first side surface; a second substrate opposed to the firstsubstrate; a polymer dispersed liquid crystal layer held between thefirst substrate and the second substrate, and including a polymer andliquid crystal molecules; and a light-emitting element opposed to an endportion of at least one of the first substrate and the second substrate,wherein the first side surface is closer to the light-emitting elementthan the second side surface, and the light-shielding layer covers atleast the first side surface of the conductive line.

According to another embodiment, a display device includes: a firstsubstrate including a conductive line having a first side surface and asecond side surface on a side opposite to the first side surface; asecond substrate including a light-shielding layer and opposed to thefirst substrate; a polymer dispersed liquid crystal layer held betweenthe first substrate and the second substrate, and including a polymerand liquid crystal molecules; and a light-emitting element opposed to anend portion of at least one of the first substrate and the secondsubstrate, wherein the first side surface is closer to thelight-emitting element than the second side surface, and thelight-shielding layer is located just above at least the first sidesurface of the conductive line.

According to yet another embodiment, a display device includes: a firstsubstrate including a scanning line and a first light-shielding layer; asecond substrate opposed to the first substrate; and a polymer dispersedliquid crystal layer held between the first substrate and the secondsubstrate, and including a polymer and liquid crystal molecules, whereinthe first light-shielding layer covers the scanning line.

Embodiments will be described hereinafter with reference to theaccompanying drawings. The disclosure is a mere example, and arbitrarychange of gist which can be easily conceived by a person of ordinaryskill in the art naturally falls within the inventive scope. To moreclarify the explanations, the drawings may pictorially show width,thickness, shape and the like of each portion as compared with actualembodiments, but they are mere examples and do not restrict theinterpretation of the invention. Furthermore, in the description andfigures of the present application, structural elements having the sameor similar functions will be referred to by the same reference numbersand detailed explanations of them that are considered redundant may beomitted.

FIG. 1 is a plan view showing a configuration example of a displaydevice DSP according to the embodiments. In the drawing, a firstdirection X and a second direction Y intersect each other, and a thirddirection Z intersects the first direction X and the second direction Y.For example, the first direction X, the second direction Y, and thethird direction Z are orthogonal to each other but may intersect at anangle other than ninety degrees. In the present specification, aposition represented by a pointing end side of an arrow indicating thethird direction Z will be referred to as “above”, and a positionrepresented by a rear end side of the arrow will be referred to as“below”. When such expressions as “a second member above a first member”and “a second member below a first member” are used, the second membermay be in contact with the first member or may be separated from thefirst member. In addition, an observation position at which the displaydevice DSP is observed is assumed to be located on the pointing end sideof the arrow indicating the third direction Z, and viewing from theobservation position toward the X-Y plane defined by the first directionX and the second direction Y is called a planar view.

In the embodiments, a display device employing polymer dispersed liquidcrystal will be explained as an example of the display device. Thedisplay device DSP comprises a display panel PNL and wiring substratesF1 to F3. In addition, the display device DSP also comprises a lightsource unit (not shown).

The display panel PNL comprises a first substrate SUB1 and a secondsubstrate SUB2. The first substrate SUB1 and the second substrate SUB2overlap in planar view. The display panel PNL includes a display area DAon which an image is displayed and a frame-shaped non-display area NDAsurrounding the display area DA. The display area DA is located in anarea where the first substrate SUB1 and the second substrate SUB2overlap. The display panel PNL includes n scanning lines G (G1 to Gn)and m signal lines S (S1 to Sm), in the display area DA. Each of n and mis a positive integer, and n may be equal to or different from m. Thescanning lines G extend in the first direction X and are arranged atintervals in the second direction Y. The signal lines S extend in thesecond direction Y and are arranged at intervals in the first directionX.

The first substrate SUB1 includes end portions E11 and E12 extending inthe first direction X, and end portions E13 and E14 extending in thesecond direction Y. The second substrate SUB2 includes end portions E21and E22 extending in the first direction X, and end portions E23 and E24extending in the second direction Y. In the example illustrated, the endportions E11 and E21, the end portions E13 and E23, and the end portionsE14 and E24 overlap each other in planar view, but may not overlap. Theend portion E22 is located between the end portion E12 and the displayarea DA in planar view. The first substrate SUB1 includes an extensionportion Ex between the end portions E12 and E22.

The wiring substrates F1 to F3 are connected to the extension portion Exand arranged in this order in the first direction X. The wiringsubstrate F1 is provided with a gate driver GD1. The wiring substrate F2is provided with a source driver SD. The wiring substrate F3 is providedwith a gate driver GD2. The wiring substrates F1 to F3 may be replacedwith a single wiring substrate.

The signal lines S are drawn to the non-display area NDA and connectedto the source driver SD. The scanning lines G are drawn to thenon-display area NDA and connected to the gate drivers GD1 and GD2. Inthe example illustrated, odd-numbered scanning lines G are drawn betweenthe end portion 514 and the display area DA and connected to the gatedriver GD2. In addition, even-numbered scanning lines G are drawnbetween the end portion E13 and the display area DA and connected to thegate driver GD1. The relationship in connection between the gate driversGD1 and GD2 and the scanning lines G is not limited to the exampleillustrated.

FIG. 2 is a perspective view showing the display device DSP shown inFIG. 1. Illustration of the wiring substrates F1 to F3 is omitted. Alight source unit LU is located above the first substrate SUB1 anddisposed along the end portion E22. The light source unit LU compriseslight-emitting elements LS corresponding to light sources and a wiringsubstrate F4 represented by a dotted line. The light-emitting elementsLS are arranged at intervals in the first direction X. Each of thelight-emitting elements LS is connected to the wiring substrate F4. Thelight-emitting elements LS are located between the first substrate SUB1and the wiring substrate F4 in the third direction Z. The light-emittingelements LS are, for example, light-emitting diodes. Each of thelight-emitting elements LS comprises a light-emitting portion EM. Thelight-emitting portion EM faces the end portion E22. The light-emittingportion EM may be in contact with the end portion E22. In addition, anair layer, an optical element, and the like may be interposed betweenthe light-emitting portion EM and the end portion E22. The end portionE22 corresponds to an incidence portion in which the light emitted fromthe light-emitting portion EM is made incident.

FIG. 3 is a cross-sectional view showing the display device DSP shown inFIG. 1. Main portions alone in the cross-section of the display deviceDSP in a Y-Z plane defined by the second direction Y and the thirddirection Z will be explained here. The display panel PNL comprises aliquid crystal layer 30 held between the first substrate SUB1 and thesecond substrate SUB2. The first substrate SUB1 and the second substrateSUB2 are bonded to each other by a sealant 40.

In the example illustrated, the light-emitting element LS is locatedabove an extension portion EX. In addition, the light-emitting elementLS is located between the wiring substrate F1 to F3 and the secondsubstrate SUB2 in the second direction Y. The light-emitting element LSemits light from the light-emitting portion EM to the end portion E22.The light incident from the end portion E22 is propagated through thedisplay panel PNL in the second direction Y as explained below. Thelight-emitting element LS may be opposed to the end portions of thefirst substrate SUB1 and the second substrate SUB2, for example, the endportions E11 and E21.

FIG. 4 is a cross-sectional view showing a configuration example of thedisplay panel PNL shown in FIG. 3. The first substrate SUB1 comprises atransparent substrate 10, a conductive line 11, an insulating layer 12,a pixel electrode 13, and an alignment film 14. The second substrateSUB2 comprises a transparent substrate 20, a common electrode 21, and analignment film 22. The second substrate SUB2 does not comprise alight-shielding layer overlapping the conductive line 11. Thetransparent substrates 10 and 20 are insulating substrates such as glasssubstrates or plastic substrates. The conductive line 11 is formed of anopaque metal material such as molybdenum, tungsten, aluminum, titaniumor silver. The conductive line 11 illustrated extends in the firstdirection X but may extend in the second direction Y. The insulatinglayer 12 is formed of a transparent insulating material. The pixelelectrodes 13 and the common electrode 21 are formed of a transparentconductive material such as indium tin oxide (ITO) or indium zinc oxide(IZO). The pixel electrodes 13 are disposed in the respective pixels PX.The common electrode 21 is disposed across the pixels PX. The alignmentfilms 14 and 22 may be horizontal alignment films having an alignmentrestriction force approximately parallel to the X-Y plane or may be avertical alignment films having an alignment restriction forceapproximately parallel to the third direction Z.

The liquid crystal layer 30 is located between the alignment films 14and 22. The liquid crystal layer 30 is a polymer dispersed liquidcrystal layer including polymer 31 which is a polymeric compound andliquid crystal molecules 32. For example, the polymer 31 is liquidcrystal polymer. The polymer 31 can be obtained by, for example,polymerizing liquid crystal monomer in a state of being aligned in apredetermined direction by the alignment restriction force of thealignment films 14 and 22. For example, the alignment treatmentdirection of the alignment films 14 and 22 agrees with the firstdirection X, and the alignment films 14 and 22 have the alignmentrestriction force in the first direction X. For this reason, the polymer31 is formed in a streaky shape or a stripe shape extending in the firstdirection X. The liquid crystal molecules 32 are dispersed in gaps ofthe polymer 31 and aligned such that their major axis extends in thefirst direction X.

The polymer 31 and the liquid crystal molecules 32 have opticalanisotropy or refractive anisotropy. The liquid crystal molecules 32 maybe positive liquid crystal molecules having a positive dielectricanisotropy or negative liquid crystal molecules having a negativedielectric anisotropy. The polymer 31 and the liquid crystal molecules32 are different in response performance to the electric field. Theresponse performance of the polymer 31 to the electric field is lowerthan the response performance of the liquid crystal molecules 32 to theelectric field. At an enlarged portion in the figure, the polymer 31 isrepresented by upward-sloping hatch lines, and the liquid crystalmolecules 32 are represented by downward-sloping hatch lines.

FIG. 5 is a cross-sectional view showing First Embodiment. The firstsubstrate SUB1 comprises the light-shielding layer 16 as well as theconductive line 11. The light-shielding layer 16 covers the conductiveline 11. In this example, “cover” implies not only a case where thelight-shielding layer 16 is in contact with the conductive line 11, butalso a case where the other member is interposed between thelight-shielding layer 16 and the conductive line 11. In the FirstEmbodiment, the light-shielding layer 16 is in contact with theconductive line 11, and covers the entire body of the conductive line11. The embodiment will be explained in more detail with reference to anenlarged view of the conductive line 11 and the light-shielding layer16, which is surrounded by a solid line.

The conductive line 11 comprise a first side surface 111, a second sidesurface 112 on a side opposite to the first side surface 111, and anupper surface 113. The first side surface 111 and the second sidesurface 112 extend in the first direction X. The first side surface 111is closer to a light-emitting element LS than the second side surface112. The light-shielding layer 16 comprises a third side surface 161,and a fourth side surface 162 on a side opposite to the third sidesurface 162. The third side surface 161 and the fourth side surface 162extend in the first direction X. The third side surface 161 is closer toa light-emitting element LS than the fourth side surface 162. Thelight-shielding layer 16 covers the first side surface 111, the secondside surface 112, and the upper surface 113. In other words, the thirdside surface 161 is closer to the light-emitting element LS than thefirst side surface 111, and the fourth side surface 162 is remoter fromthe light-emitting element LS than the second side surface 112. Thelight-shielding layer 16 is in contact with an insulating layer 17located under the conductive line 11, on a side closer to thelight-emitting element LS than the first side surface 111.

The light-shielding layer 16 is formed of a material having a lowreflectance, low light-absorption index, or low light-shieldingproperty. For example, the light-shielding layer 16 may be formed of ametal material such as molybdenum or an insulating material colored inblack or the like.

FIG. 6 is a cross-sectional view showing Second Embodiment. The SecondEmbodiment is different from the First Embodiment with respect to afeature that a fourth side surface 162 is located just above a secondside surface 112. In the example illustrated, the second side surface112 and the fourth side surface 162 are located in the same planeparallel to X-Z plane defined by the first direction X and the thirddirection Z, but are not limited to this example. For example, at leastone of the second side surface 112 and the fourth side surface 162 maybe inclined or the second side surface 112 and the fourth side surface162 may be inclined at different angles of inclination. In the SecondEmbodiment, at least a part of the fourth side surface 162 may belocated on the second side surface 112. The first side surface 111 andthe upper surface 113 are covered with a light-shielding layer 16similarly to the First Embodiment.

FIG. 7 is a cross-sectional view showing Third Embodiment. The ThirdEmbodiment is different from the First Embodiment with respect to afeature that a light-shielding layer 16 does not cover a second sidesurface 112. A fourth side surface 162 is located on an upper surface113. The fourth side surface 162 is closer to a light-emitting elementLS than the second side surface 112. A first side surface 111 and a partof the upper surface 113 are covered with the light-shielding layer 16similarly to the First Embodiment.

As explained with reference to FIG. 2, light-emitting elements LS arearranged in the first direction X, and light emitted from thelight-emitting elements LS is propagated in the second direction Y. Incontrast, the first side surface 111 extends in the first direction Xand intersects the direction of propagation of the light (or the firstside surface 111 is substantially orthogonal to the direction ofpropagation of the light).

According to the First to Third Embodiments, the light-shielding layer16 covers at least the first side surface 111, of the conductive line11. For this reason, when the light from the light-emitting element LSis propagated through the display panel PNL, undesired reflection orscattering on the first side surface 111 facing the light-emittingelement LS side of the conductive line 11 can be suppressed. Therefore,degradation in display quality of an image displayed on the displaypanel PNL can be suppressed.

In addition, according to the First Embodiment, since thelight-shielding layer 16 covers the first side surface 111, the secondside surface 112, and the upper surface 113 of the conductive line 11,undesired reflection or scattering on each of the surfaces of theconductive line 11 can be suppressed.

In addition, according to the Second Embodiment and the ThirdEmbodiment, since the light-shielding layer 16 is not disposed on theside remoter from the light-emitting element LS than the second sidesurface 112, an area covered with the light-shielding layer 16, of thepixel can be reduced and an area contributing to the display per pixelcan be increased.

Furthermore, according to the Third Embodiment, since a part of theupper surface 113 is exposed from the light-shielding layer 16, the partof the upper surface 113 can be used as a reflective surface forpropagating the light from the light-emitting element LS through thedisplay panel PNL, and the light propagation efficiency or light useefficiency can be improved.

FIG. 8 is a cross-sectional view showing a first configuration exampleof First Embodiment. The conductive line 11 comprises a first edge E1and a second edge E2 located at outermost portions in the seconddirection Y. The second edge E2 is located on a side opposite to thefirst edge E1. The first edge E1 is closer to the light-emitting elementLS than the second edge E2. The light-shielding layer 16 comprises athird edge E3 and a fourth edge E4 located at outermost portions in thesecond direction Y. The third edge E3 is closer to the light-emittingelement LS than the first edge E1. The fourth edge E4 is remoter fromthe light-emitting element LS than the second edge E2. Thelight-shielding layer 16 has a first width W1 between the first edge E1and the third edge E3, and a second width W2 between the second edge E2and the fourth edge E4. Each of the first width W1 and the second widthW2 is a length of the light-shielding layer 16 in the second directionY. The first width W1 is larger than or equal to the second width W2.

The first side surface 111 is inclined to the insulating layer 17 at anacute angle, i.e., first angle of inclination θ11. The second sidesurface 112 is inclined similarly to the first side surface 111. In theexample illustrated, the first edge E1 corresponds to a portion which isthe closest to the insulating layer 17, of the first side surface 111.Similarly, the second edge E2 corresponds to a portion which is theclosest to the insulating layer 17, of the second side surface 112. Thethird side surface 161 is inclined to the insulating layer 17 at asecond angle of inclination θ16 larger than the first angle ofinclination θ11. For example, the second angle of inclination θ16 isninety degrees. The fourth side surface 162 is inclined similarly to thethird side surface 161. In the example illustrated, the third edge E3corresponds to a portion which is the closest to the insulating layer17, of the third side surface 161. Similarly, the fourth edge E4corresponds to a portion which is the closest to the insulating layer17, of the fourth side surface 162.

FIG. 9 is a cross-sectional view showing a second configuration exampleof the First Embodiment. The second configuration example is differentfrom the first configuration example with respect to a feature that asecond angle of inclination θ16 is an acute angle. The third sidesurface 161 and the fourth side surface 162 are inclined to theinsulating layer 17 at an acute angle, i.e., second angle of inclinationθ16. In the second configuration example, first thickness T1 of thelight-shielding layer 16 overlapping the first side surface 111 islarger than or equal to second thickness T2 of the light-shielding layer16 overlapping the second side surface 112. Each of the first thicknessT1 and the second thickness T2 is a length of the light-shielding layer16 in the third direction Z.

FIG. 10 is a cross-sectional view showing a third configuration exampleof the First Embodiment. The third configuration example is differentfrom the first configuration example with respect to a feature that thesecond angle of inclination θ16 is an obtuse angle. The third sidesurface 161 and the fourth side surface 162 are inclined to theinsulating layer 17 at an obtuse angle, i.e., second angle ofinclination θ16. For this reason, even if the light propagating thedisplay panel PNL is reflected on the third side surface 161, upwardreflection or scattering in the third direction Z can be suppressed.

FIG. 11 is a cross-sectional view showing a fourth configuration exampleof Second Embodiment. In the Second Embodiment, a fourth edge E4 islocated just above a second edge E2. A third edge E3 is closer to alight-emitting element LS than a first edge E1, similarly to the FirstEmbodiment shown in FIG. 8 to FIG. 10.

FIG. 12 is a cross-sectional view showing a fifth configuration exampleof the Second Embodiment. The fifth configuration example is differentfrom the fourth configuration example with respect to a feature that thefourth edge E4 is located on a second side surface 112. In other words,the fourth edge E4 is closer to the first edge E1 than the second edgeE2. The third edge E3 is closer to a light-emitting element LS than thefirst edge E1, similarly to the First Embodiment shown in FIG. 8 to FIG.10.

FIG. 13 is a cross-sectional view showing a sixth configuration exampleof Third Embodiment. In the Third Embodiment, a fourth edge E4 islocated on an upper surface 113. A third edge E3 is closer to alight-emitting element LS than a first edge E1. The third side surface161 and the fourth side surface 162 in the fourth to sixth configurationexamples may be inclined similarly to the second and third configurationexamples.

FIG. 14 is a cross-sectional view showing a seventh configurationexample of a conductive line 11 and a light-shielding layer 16. Theconductive line 11 is composed of a multilayer body comprising a firstlayer L1, a second layer L2, and a third layer L3. For example, thefirst layer L1 and the third layer L3 are formed of the same material,and the second layer L2 is formed of a material different from thematerial of the first layer L1. For example, the first layer L1 and thethird layer L3 are formed of molybdenum or titanium, and the secondlayer L2 is formed of aluminum. The conductive line 11 can be obtainedby forming a stacked layer body of three metal layers, i.e., amolybdenum layer, an aluminum layer, and a molybdenum layer on theinsulating layer 17 and entirely patterning the stacked layer body. Thelight-shielding layer 16 is formed of a material having a lowreflectance, low light-absorption index, or low light-shielding propertyand covers the conductive line 11. For example, the light-shieldinglayer 16 is formed of an organic material.

FIG. 15 is a cross-sectional view showing an eighth configurationexample of the conductive line 11 and the light-shielding layer 16. Aneighth configuration example shown in FIG. 15 is different from theseventh configuration example shown in FIG. 14 with respect to across-sectional shape of the light-shielding layer 16. The conductiveline 11 is composed of the same multilayer body as the seventhconfiguration example. The light-shielding layer 16 is formed of amaterial having a low reflectance, low light-absorption index, or lowlight-shielding property and covers the conductive line 11. For example,the light-shielding layer 16 is formed of an inorganic material.

FIG. 16 is a cross-sectional view showing a ninth configuration exampleof the conductive line 11 and the light-shielding layer 16. Theconductive line 11 is composed of a multilayer body comprising a firstlayer L1 and a second layer L2. The light-shielding layer 16 is formedof, for example, a metal material such as molybdenum and covers theconductive line 11. The conductive line 11 can be obtained by forming,for example, a stacked layer body of a molybdenum layer and an aluminumlayer on the insulating layer 17 and entirely patterning the stackedlayer body. In addition, the light-shielding layer 16 can be obtained byforming, for example, a molybdenum layer on the insulating layer 17 andthe conductive line 11 and patterning the molybdenum layer. For example,the first layer L1 and the light-shielding layer 16 are formed of thesame material and are, for example, molybdenum layers.

FIG. 17 is a cross-sectional view showing Fourth Embodiment. The FourthEmbodiment is different from the First Embodiment with respect to afeature that a second substrate SUB2 comprises a light-shielding layer23. The light-shielding layer 23 is located just above the conductiveline 11. In the Fourth Embodiment, the light-shielding layer 23 isopposed to the entire body of the conductive line 11. The embodimentwill be explained in more detail with reference to an enlarged view ofthe conductive line 11 and the light-shielding layer 23, which issurrounded by a solid line.

The light-shielding layer 23 is formed of the same material as thelight-shielding layer 16. The light-shielding layer 23 comprises a fifthside surface 231, and a sixth side surface 232 on a side opposite to thefifth side surface 231. The fifth side surface 231 is closer to alight-emitting element LS than the sixth side surface 232. The fifthside surface 231 is closer to the light-emitting element LS than thefirst side surface 111, and the sixth side surface 232 is remoter fromthe light-emitting element LS than the second side surface 112.

In addition, the light-shielding layer 23 comprises a fifth edge E5 anda sixth edge E6 located at outermost portions in the second direction Y.The fifth edge E5 is closer to the light-emitting element LS than thefirst edge E1. The sixth edge E6 is remoter from the light-emittingelement LS than the second edge E2. The light-shielding layer 23 has athird width W3 between the first edge E1 and the fifth edge E5, and afourth width W4 between the second edge E2 and the sixth edge E6. Thethird width W3 is larger than or equal to the fourth width W4.

FIG. 18 is a cross-sectional view showing Fifth Embodiment. The FifthEmbodiment is different from the Fourth Embodiment with respect to afeature that a sixth side surface 232 is located just above a secondside surface 112. A sixth edge E6 is located just above a second edgeE2. Similarly to the Fourth Embodiment, a fifth side surface 231 iscloser to a light-emitting element LS than a first side surface 111, anda fifth edge E5 is closer to the light-emitting element LS than a firstedge E1.

FIG. 19 is a cross-sectional view showing Sixth Embodiment. The SixthEmbodiment is different from the Fourth Embodiment with respect to afeature that a sixth side surface 232 is closer to a light-emittingelement LS than a second side surface 112. In other words, alight-shielding layer 23 is not disposed just above the second sidesurface 112. A sixth edge E6 is closer to the light-emitting element LSthan a second edge E2.

According to the Fourth to Sixth Embodiments, as explained above, thelight-shielding layer 23 is located just above at least the first sidesurface 111, of the conductive line 11. For this reason, when the lightfrom the light-emitting element LS is propagated through the displaypanel PNL, even if undesired reflected light or scattered light isgenerated on the first side surface 111 facing the light-emittingelement LS side of the conductive line 11, the reflected light orscattered light is blocked by the light-shielding layer 23. Therefore,degradation in display quality of an image displayed on the displaypanel PNL can be suppressed.

FIG. 20 is a cross-sectional view showing a tenth configuration example.The conductive line 11 is formed similarly to the first configurationexample and the like. In the light-shielding layer 23, the fifth sidesurface 231 is inclined to an insulating layer 24 at an acute angle,i.e., third angle of inclination θ23. The sixth side surface 232 isinclined similarly to the fifth side surface 231. For this reason, evenif the light propagating the display panel PNL is reflected on the fifthside surface 231, upward reflection or scattering in the third directionZ can be suppressed.

FIG. 21 is a cross-sectional view showing an eleventh configurationexample. The eleventh configuration example is different from the tenthconfiguration example with respect to a feature that a reflective layer25 is provided between the light-shielding layer 23 and the conductiveline 11. In the example illustrated, the reflective layer 25 is incontact with the light-shielding layer 23. A width W25 of the reflectivelayer 25 is smaller than the width W23 of the light-shielding layer 23.In addition, each of edges E251 and E252 of the reflective layer 25 islocated between the fifth edge E5 and the sixth edge E6 of thelight-shielding layer 23. For this reason, even if the light propagatingthe display panel PNL is reflected on the first side surface 111, thereflected light is reflected on the reflective layer 25 and can befurther propagated through the display panel PNL. In other words, sincethe reflected light is hardly absorbed by the light-shielding layer 23,the light use efficiency can be improved.

FIG. 22 is a cross-sectional view showing Seventh Embodiment. TheSeventh Embodiment is different from the First Embodiment with respectto a feature that a first substrate SUB1 comprises a conductive line 11and a light-shielding layer (first light-shielding layer) 16 and asecond substrate SUB2 comprises a light-shielding layer (secondlight-shielding layer) 23. According to the Seventh Embodiment, the sameadvantages as those of the First Embodiment can be obtained and, even ifundesired reflected light or scattered light is generated in thelight-shielding layer 16, the reflected light or scattered light isblocked by the light-shielding layer 23. Therefore, degradation indisplay quality of an image displayed on the display panel PNL can besuppressed.

Next, a polymer dispersed liquid crystal layer (hereinafter simplycalled a liquid crystal layer 30) will be explained in more detail.

FIG. 23 is an illustration schematically showing a liquid crystal layer30 in a transparent state. The example illustrated corresponds to astate in which no voltage is applied to the liquid crystal layer 30 (forexample, a state in which a potential difference between a pixelelectrode 13 and a common electrode 21 is approximately zero). Anoptical axis Ax1 of the polymers 31 and an optical axis Ax2 of theliquid crystal molecules 32 are parallel to each other. In the exampleillustrated, each of the optical axis Ax1 and the optical axis Ax2 isparallel to the first direction X. The polymers 31 and the liquidcrystal molecules 32 have approximately equivalent refractiveanisotropy. In other words, ordinary refractive indexes of the polymers31 and the liquid crystal molecules 32 are approximately equivalent toeach other, and extraordinary refractive indexes of the polymers 31 andthe liquid crystal molecules 32 are approximately equivalent to eachother. For this reason, refractive index difference is hardly presentbetween the polymers 31 and the liquid crystal molecules 32 in alldirections including the first direction X, the second direction Y, andthe third direction Z. For this reason, a light beam L1 incident on theliquid crystal layer 30 in the third direction Z is transmitted whilehardly scattered in the liquid crystal layer 30. A light beam L2incident in a direction oblique with respect to the third direction Z ishardly scattered in the liquid crystal layer 30, either. For thisreason, high transparency can be obtained. The state illustrated in FIG.23 is called a transparent state. For example, the light beam L3corresponds to the light emitted from the light-emitting element LSshown in FIG. 3 and the like, and is propagated in a direction oppositeto the direction represented by an arrow of the second direction Y whilehardly scattered in the liquid crystal layer 30.

FIG. 24 is an illustration schematically showing the liquid crystallayer 30 in a scattering state. The example illustrated corresponds to astate in which a voltage is applied to the liquid crystal layer 30 (forexample, a state in which a potential difference between the pixelelectrode 13 and the common electrode 21 is higher than or equal to athreshold value). As explained above, the response performance of thepolymer 31 to the electric field is lower than the response performanceof the liquid crystal molecules 32 to the electric field. For example,the alignment direction of the polymers 31 is hardly varied irrespectiveof the presence or absence of the electric field. In contrast, thealignment direction of the liquid crystal molecules 32 is varied inaccordance with the electric field in a state in which a voltage higherthan or equal to the threshold value is applied to the liquid crystallayer 30. In other words, as illustrated in the drawing, the opticalaxis Ax1 is substantially parallel to the first direction X while theoptical axis Ax2 is oblique to the first direction X. If the liquidcrystal molecules 32 are positive liquid crystal molecules, the liquidcrystal molecules 32 are aligned such that their major axes correspondto the electric field. An electric field between the pixel electrode 13and the common electrode 21 is formed in the third direction Z. For thisreason, the liquid crystal molecules 32 are aligned such that theirmajor axes or the optical axes Ax2 correspond to the third direction Z.In other words, the optical axes Ax1 and optical axes Ax2 intersect eachother. A large refractive index difference is therefore generatedbetween the polymers 31 and the liquid crystal molecules 32 in alldirections including the first direction X, the second direction Y, andthe third direction Z. The light beams L1 to L3 incident on the liquidcrystal layer 30 are thereby scattered in the liquid crystal layer 30.The state illustrated in FIG. 24 is called a scattering state.

FIG. 25 is a cross-sectional view showing a display panel PNL in a casewhere the liquid crystal layer 30 is in a transparent state. A lightbeam L11 emitted from the light-emitting element LS is made incident onthe display panel PNL from the end portion E22 and is propagated througha transparent substrate 20, the liquid crystal layer 30, a transparentsubstrate 10, and the like. The liquid crystal layer 30 overlapping aconductive line 11 and a pixel electrode 13 is in a transparent state.For this reason, the light beam L11 is hardly scattered in the liquidcrystal layer 30, and hardly leaks from a lower surface 10B of thetransparent substrate 10 or an upper surface 20T of the transparentsubstrate 20.

An external light beam L12 incident on the display panel PNL istransmitted and hardly scattered in the liquid crystal layer 30. Inother words, the external light beam L12 incident on the display panelPNL from the lower surface 10B is transmitted through the upper surface20T, and the external light beam L12 incident on the display panel PNLfrom the upper surface 20T is transmitted through the lower surface 10B.For this reason, the user can visually recognize a background on thelower surface 10B side through the display panel PNL when observing thedisplay panel PNL from the upper surface 20T side. Similarly, the usercan visually recognize a background on the upper surface 20T sidethrough the display panel PNL when observing the display panel PNL fromthe lower surface 10B side.

FIG. 26 is a cross-sectional view showing the display panel PNL in acase where the liquid crystal layer 30 is in a scattering state. A lightbeam L21 emitted from the light-emitting element LS is made incident onthe display panel PNL from the end portion E22 and is propagated througha transparent substrate 20, the liquid crystal layer 30, a transparentsubstrate 10, and the like. In the example illustrated, the liquidcrystal layer 30 overlapping the conductive line 11 is maintained in atransparent state. In addition, the liquid crystal layer 30 overlappinga pixel electrode 13A to which no voltage is applied is in a transparentstate. For this reason, the light beam L21 is hardly scattered in anarea of the liquid crystal layer 30, which overlaps the pixel electrode11 and the pixel electrode 13A. In contrast, the liquid crystal layer 30overlapping a pixel electrode 13B to which a voltage is applied is in ascattered state. For this reason, the light beam L21 is scattered in anarea of the liquid crystal layer 30, which overlaps the pixel electrode13B. A scattered light beam L211 which is a part of the light beam L21is transmitted through the upper surface 20T, a scattered light beamL212 which is another part of the light beam L21 is transmitted throughthe lower surface 10B, and the other scatter light beam is propagatedthrough the inside of the display panel PNL.

In the area overlapping the pixel electrode 13A to which the voltage isnot applied, an external light beam L22 incident on the display panelPNL is transmitted and hardly scattered in the liquid crystal layer 30,similarly to the external light beam L12 shown in FIG. 25. In the areaoverlapping the pixel electrode 13B to which the voltage is applied, anexternal light beam L23 incident from the lower surface 10B is scatteredin the liquid crystal layer 30 and a light beam L231 which is a part ofthe external light beam L23 is transmitted through the upper surface20T. In addition, an external light beam L24 incident from the uppersurface 20T is scattered in the liquid crystal layer 30 and a light beamL241 which is a part of the external light beam L24 is transmittedthrough the lower surface 103. For this reason, the user can visuallyrecognize a color of the light beam L21 in the area overlapping thepixel electrode 13B when observing the display panel PNL from the uppersurface 20T side. In addition, since the external light beam L231 istransmitted through the display panel PNL, the user can also visuallyrecognize the background on the lower surface 10B side through thedisplay panel PNL. Similarly, the user can visually recognize a color ofthe light beam L21 in the area overlapping the pixel electrode 13B whenobserving the display panel PNL from the lower surface 10B side. Inaddition, since the external light beam L241 is transmitted through thedisplay panel PNL, the user can also visually recognize the backgroundon the upper surface 20T side through the display panel PNL. In the areaoverlapping the pixel electrode 13A, the color of the light beam L21 canhardly be recognized visually and the user can visually recognize thebackground through the display panel PNL since the liquid crystal layer30 is in the transparent state.

Next, an example will be explained.

FIG. 27 is a plan view showing an example of the pixel PX. In theexample illustrated, the pixel PX is sectioned by two signal lines Sarranged in the first direction X and two scanning lines G arranged inthe second direction Y. The pixel PX comprises a switching element SWand a pixel electrode 13. The switching element SW is, for example, athin-film transistor and is electrically connected to the scanning lineG and the signal line S. More specifically, the switching element SWcomprises a semiconductor layer SC, a gate electrode GE, a sourceelectrode SE, and a drain electrode DE. The gate electrode GE is formedintegrally with the scanning line G. The light-shielding layer 16overlaps the scanning lines G and the gate electrode GE. In the exampleillustrated, the switching element SW is a bottom-gate type switchingelement in which a gate electrode GE is located below the semiconductorlayer SC, but may be a top-gate type switching element in which a gateelectrode GE is located above the semiconductor layer SC. Thesemiconductor layer SC is formed of, for example, amorphous silicon, butmay be formed of polycrystalline silicon or an oxide semiconductor. Thesource electrode SE is formed integrally with the signal line S and isin contact with the semiconductor layer SC. The drain electrode DE isremote from the source electrode SE and is in contact with thesemiconductor layer SC. The pixel electrode 13 overlaps the drainelectrode DE and is in contact with the drain electrode DE through thecontact hole CH.

In addition, a capacitive line C is disposed between two scanning linesG. The pixel electrode 13 overlaps the capacitive line C. A storagecapacitance is formed at a portion where the capacitive line C and thepixel electrode 13 overlap.

FIG. 28 is a cross-sectional view seen along line A-B in the pixel PXshown in FIG. 27. In the first substrate SUB1, the gate electrode GE anda scanning line G are located on the transparent substrate 10 andcorrespond to, for example, the conductive lines 11 shown in FIG. 4. Thelight-shielding layer 16 is in contact with the gate electrode GE andthe scanning line G, and covers the gate electrode GE and the scanningline G. An insulating layer 121 covers the light-shielding layer 16 andthe transparent substrate 10. The semiconductor layer SC is located onthe insulating layer 121 just above the gate electrode GE. Each of thesource electrode SE and the drain electrode DE is located on theinsulating layer 121 and is in contact with the semiconductor layer SC.An insulating layer 122 covers the semiconductor layer SC, the sourceelectrode SE, the drain electrode DE, and the insulating layer 121. Theinsulating layer 123 covers the insulating layer 122. The insulatinglayers 121 to 123 correspond to, for example, the insulating layer 12shown in FIG. 4. The insulating layers 121 and 122 are formed of, forexample, a transparent inorganic insulating material such as siliconnitride or silicon oxide. The insulating layer 123 is formed of, forexample, a transparent organic insulating material such as acrylicresin. The pixel electrode 13 is located on the insulating layer 123.The pixel electrode 13 is in contact with the drain electrode DE at thecontact hole CH which penetrates the insulating layers 122 and 123. Thealignment film 14 covers the pixel electrode 13 and the insulating layer123.

In the second substrate SUB2, the light-shielding layer 23 is locatedbelow transparent substrate 20 and is also located just above the gateelectrode GE and the scanning line G. The overcoat layer 24 covers thetransparent substrate 20 and the light-shielding layer 23. The commonelectrode 21 is located below the overcoat layer 24. The alignment film22 covers the common electrode 21. The liquid crystal layer 30 is incontact with the alignment films 14 and 21.

According to the above-explained embodiment, the scanning line Gextending in the first direction X is covered with the light-shieldinglayer 16, and the light-shielding layer 23 is located just above thescanning line G. For this reason, the degradation in display qualitywhich results from undesired reflection or scattering on the sidesurfaces of the scanning line G can be suppressed. As shown in FIG. 27,various conductive layers such as the capacitive line C, the sourceelectrode SE, and the drain electrode DE comprise side surfaces in thefirst direction X, similarly to the scanning line G. For this reason,undesired reflection or scattering can be further suppressed byshielding the side surfaces of the capacitive line C, the sourceelectrode SE, and the drain electrode DE in at least the first directionX against the light.

As explained above, according to the embodiments, in the configurationthat the conductive layer of the conductive line, the electrode, and thelike has the side surfaces with a comparatively high reflectance and theside surfaces face the light-emitting element LS side and intersect thedirection of propagation of the light, undesired reflection orscattering can be suppressed by covering the side surfaces with thelight-shielding layer 16, and undesired reflected light or scatteredlight can be blocked by arranging the light-shielding layer 23 justabove the side surfaces. The display device capable of suppressingdegradation in display quality can be therefore provided.

The present invention is not limited to the embodiments described abovebut the constituent elements of the invention can be modified in variousmanners without departing from the spirit and scope of the invention.Various aspects of the invention can also be extracted from anyappropriate combination of a plurality of constituent elements disclosedin the embodiments. For example, some structural elements may be deletedfrom the entire structural elements in the embodiments. Furthermore, theconstituent elements described in different embodiments may be combinedarbitrarily.

What is claimed is:
 1. A display device, comprising: a first substratecomprising a light-shielding layer and a conductive line having a firstside surface and a second side surface on a side opposite to the firstside surface; a second substrate opposed to the first substrate; apolymer dispersed liquid crystal layer held between the first substrateand the second substrate, and including a polymer and liquid crystalmolecules; and a light-emitting element opposed to an end portion of atleast one of the first substrate and the second substrate, wherein thefirst side surface is closer to the light-emitting element than thesecond side surface, and the light-shielding layer covers at least thefirst side surface of the conductive line.
 2. The display device ofclaim 1, wherein the conductive line has a first edge and a second edgeon a side opposite to the first edge, the first edge is closer to thelight-emitting element than the second edge, the light-shielding layerhas a third edge closer to the light-emitting element than the firstedge, and a fourth edge remoter from the light-emitting element than thesecond edge, and a first width between the first edge and the third edgeis larger than or equal to a second width between the second edge andthe fourth edge.
 3. The display device of claim 1, wherein theconductive line has a first edge and a second edge on a side opposite tothe first edge, the first edge is closer to the light-emitting elementthan the second edge, and the light-shielding layer has a third edgecloser to the light-emitting element than the first edge, and a fourthedge located just above the second edge.
 4. The display device of claim1, wherein the light-shielding layer does not cover the second sidesurface.
 5. The display device of claim 4, wherein the conductive linehas a first edge and a second edge on a side opposite to the first edge,the first edge is closer to the light-emitting element than the secondedge, and the light-shielding layer has a third edge closer to thelight-emitting element than the first edge, and a fourth edge locatedjust above the second side surface.
 6. The display device of claim 4,wherein the conductive line has a first edge, a second edge on a sideopposite to the first edge, and an upper surface between the first edgeand the second edge, the first edge is closer to the light-emittingelement than the second edge, and the light-shielding layer has a thirdedge closer to the light-emitting element than the first edge, and afourth edge located just above the upper surface.
 7. The display deviceof claim 1, wherein the light-shielding layer includes a third sidesurface closer to the light-emitting element than the first sidesurface, and the third side surface is inclined at an acute angle ofinclination.
 8. The display device of claim 7, wherein a first thicknessof the light-shielding layer overlapping the first side surface islarger than or equal to a second thickness of the light-shielding layeroverlapping the second side surface.
 9. The display device of claim 1,wherein the light-shielding layer includes a third side surface closerto the light-emitting element than the first side surface, and an angleof inclination of the first side surface is different from an angle ofinclination of the third side surface.
 10. The display device of claim9, wherein the third side surface is inclined at an obtuse angle ofinclination.
 11. The display device of claim 1, wherein the conductiveline is composed of a multilayer body formed by stacking a first layer,a second layer, and a third layer in order, the first layer and thethird layer are formed of the same material, the second layer is formedof a material different from a material of the first layer, and thelight-shielding layer is formed of an organic material or an inorganicmaterial.
 12. The display device of claim 1, wherein the conductive lineis composed of a multilayer body formed by stacking a first layer and asecond layer, the light-shielding layer is formed of a metal material,and the first layer and the light-shielding layer are formed of the samematerial.
 13. A display device, comprising: a first substrate comprisinga conductive line having a first side surface and a second side surfaceon a side opposite to the first side surface; a second substratecomprising a light-shielding layer and opposed to the first substrate; apolymer dispersed liquid crystal layer held between the first substrateand the second substrate, and including a polymer and liquid crystalmolecules; and a light-emitting element opposed to an end portion of atleast one of the first substrate and the second substrate, wherein thefirst side surface is closer to the light-emitting element than thesecond side surface, and the light-shielding layer is located just aboveat least the first side surface of the conductive line.
 14. The displaydevice of claim 13, wherein the conductive line has a first edge and asecond edge on a side opposite to the first edge, the first edge iscloser to the light-emitting element than the second edge, thelight-shielding layer has a fifth edge closer to the light-emittingelement than the first edge, and a sixth edge on a side opposite to thethird edge, and a third width between the first edge and the fifth edgeis larger than or equal to a fourth width between the second edge andthe sixth edge.
 15. The display device of claim 13, wherein theconductive line has a first edge and a second edge on a side opposite tothe first edge, the first edge is closer to the light-emitting elementthan the second edge, and the light-shielding layer has a fifth edgecloser to the light-emitting element than the first edge, and a sixthedge located just above the second edge.
 16. The display device of claim13, wherein the conductive line has a first edge, a second edge on aside opposite to the first edge, and an upper surface between the firstedge and the second edge, the first edge is closer to the light-emittingelement than the second edge, and the light-shielding layer has a thirdedge closer to the light-emitting element than the first edge, and asixth edge closer to the light-emitting element than the second edge.17. The display device of claim 13, wherein the light-shielding layerincludes a fifth side surface closer to the light-emitting element thanthe first side surface, and the fifth side surface is inclined at anacute angle of inclination.
 18. The display device of claim 13, furthercomprising: a reflective layer located between the light-shielding layerand the conductive line.
 19. A display device, comprising: a firstsubstrate comprising a scanning line and a first light-shielding layer;a second substrate opposed to the first substrate; and a polymerdispersed liquid crystal layer held between the first substrate and thesecond substrate, and including a polymer and liquid crystal molecules,wherein the first light-shielding layer covers the scanning line. 20.The display device of claim 19, wherein the second substrate comprises asecond light-shielding layer, and the second light-shielding layer islocated just above the scanning line.